how long a mailbox can be 95% synchronized after completed the migration to Office 365

Question

We are migrating mailboxes to Office 365 and I would like to know how long a mailbox can be 95% synchronized (days). I mention it since I would like to have a mailbox in that state for several days until we have the connectivity ready for the migration.

Cheers

Answer 1

@Juan Manuel Munayco Coronado
There is no specific time for mailbox migration, it depends on many factors such as the size of mailbox, the speed and quality of the network.
As said in above article, all batches with Completed status will be removed after 60 days. So, give more time for mailbox migration, it will deleted automatically after completed. You only need to pay attention to the failed migration requests, if any.

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

After 60 days they will be stopped. After 90 removed

https://learn.microsoft.com/en-us/exchange/mailbox-migration/manage-migration-batches

Migration batches with a status of Synced that have no administrator-initiated activity (for example, no administrator has stopped and restarted a migration batch or edited a migration batch) for the last 60 days will be stopped. All batches with Stopped or Failed status will be removed after 90 days. All batches with Completed status will be removed after 60 days.